The present invention is directed to winding tubes, and more particularly to a reusable winding tube in which the fibers or filaments are more easily removed from the peripheral starting groove which carries the waste bunch once the package has been emptied.
In conventional automatic winding operations, yarn is wound onto a cylindrical laminated paper tube (hereinafter referred to a "paper tube"). One end of the paper tube includes a starting groove cut into the surface thereof (U.S. Pat. No. 3,103,305). The starting groove is divided into two arcuate portions. The greater arcuate portion (approximately 270.degree. ) is wider and referred to as the lead-in portion, while the smaller (approximately 90.degree. ) arcuate portion (locking portion) is narrower and locks one or more of the initial strands of yarn therein during the initial few turns of the automatic winding operation. These strands are hereinafter and commonly referred to as the "waste bunch." The completed yarn package is removed from the winding machine, and stored or shipped for further processing. During further processing, the yarn is then removed from the yarn carrier.
When the yarn is removed from the package, the last few strands of the waste bunch remain wedged in the lead-in and locking portions of the starting groove. Because of the construction of conventional paper tubes, it is very difficult to remove these remaining strands of fibrous or filamentary material. Previous attempts to remove these strands have included vacuum stripping, cutting of the strands, or a combination of both. Neither technique is satisfactory, because vacuum stripping simply does not remove all the fibrous or filamentary material. Cutting the bunch generally results in damage to the surface of the paper tube making it unsuitable for further use. Such damage occurs when the laminates of the paper tube are nicked, cut, or otherwise interrupted. Use of a damaged tube at high speeds then tends to result in delamination.
As a result, conventional paper winding tubes are generally to reusable. There have been some attempts to reuse the tubes at least once by providing a starting groove at each end of the tube. However, often the paper tube is otherwise damaged during the doffing and emplacement operations which substantially eliminates the reuse of the paper tubes. Conventional paper tubes are relatively expensive (25 25.cent. to $1.00 apiece) and hundreds of thousands or even millions per year are used by typical yarn manufacturers. Thus the cost of non-reusable yarn carriers is extremely high.
Merely the replacement of paper tubes with a stronger material such as a polymeric material or aluminum is not an obvious solution. First, the proper configuration of the starting groove cannot be molded or machined satisfactorily in the wall of a polymeric or metallic tube. Secondly, merely a change of material does not solve the problems created by the necessity to clean the starting groove. It is still not easy to vacuum the fibers from the starting groove, and utilizing a knife will still damage the surface of the tube so that it cannot be reused. While the use of polymeric material or metallic material such as aluminum is a first step toward an improved tube, it has been found that some improved technique for cleaning of the starting groove is necessary in order to achieve a reusable winding tube.
Examples in the prior art of separable yarn carriers are illustrated in the U.S. Pat. Nos. to Chaffin No. 1,991,880; Moss No. 2,837,297; and Underwood No. 3,971,526. However, none of these yarn carriers are for high speed automatic winding operations or solve the problems attendant to the removal of residual fibers and filaments from a starting groove.
In our copending application, Ser. No. 200,939 filed May 31, 1988, the tube is formed entirely of a polymeric or metallic material in two separable parts, i.e. the main hollow tube portion and a removable end cap. A starting groove of unique shape is formed between the abutting end walls of the end cap and hollow tube to receive the waste bunch during the automatic winding operation. After the yarn package is emptied the end cap is removed or partially removed from the hollow tube portion, the fibers or filaments vacuumed or stripped away, and the end cap replaced. The yarn carrier is then ready for reuse. A French Pat. No. 2,463,088 to Viscosuisse, S.A. shows a somewhat related concept in which a paper tube has a friction fit (apparently plastic) slip-on ring releasably attached to the end thereof. The slip-on ring has resilient fingers that fit inside the paper tube and hold the two components in assembled relation.
While both of the separable yarn carriers identified hereinabove have desirable characteristics and suggest improvements that might solve the groove cleaning problem, they present new problems. The all polymeric or metallic tube represents a significant change from the industry accepted paper tube. Obviously, the dies and/or molds for such an approach are very expensive. Further, the industry strongly prefers paper tubes for two reasons. First, from the standpoint of safety, if a paper tube fails at high speeds, it merely delaminates and no damage to equipment or personnel occurs. However, if a polymeric or metallic tube should fail, a large number of brittle pieces are released which could be dangerous to personnel or equipment. Secondly, most yarn carriers are surface driven by engaging the end portions with drive means. The drive wheels are designed to be compatible with paper and tend to scar conventional polymeric and other surfaces with a result that they become prematured, worn and unusable.
The French patent (No. 2,463,088) is illustrative of a yarn carrier having a separable end cap or ring for facilitating removal of yarn from the starting groove in preparation for reuse. However, the end cap (apparently plastic) is not compatible with the startup friction generated by conventional drive wheels, and the resilient or spring fingers are not a satisfactory connecting technique to adequately hold the end cap and the hollow tube together. In addition, the paper hollow tube is not capable of being threaded on the inner surface to effect a more secure threaded connection between the end cap and paper tube.
In the broadest aspect of the present invention, a hollow paper tube and separable paper end cap forming a starting groove therebetween are each provided with a rigid insert of polymeric or metallic material. The inserts include mating surface configurations which selectively effect a secure attachment of the end cap to the tube, yet allow for selective separation of the end cap and hollow tube to remove loose fibers from the starting groove. Since the exposed surfaces of the resulting yarn carrier is all paper, and the only rigid material is the relatively small, underlying inserts, the safety concerns of the industry are fulfilled and the desirable paper surface is maintained.
In its more specific aspects the reusable winding carrier of the present invention includes a hollow, predominantly paper, tube having an outer, substantially cylindrical surface adapted to carry a filamentary or fibrous yarn thereon. The end cap includes an outer substantially cylindrical paper surface generally of the same radius as the outer surface of the hollow tube. The end cap and hollow tube are each provided with underlying inserts having mating threads or other attachment means for releasably mounting the end cap on at least one end of the hollow tube. It is possible that both ends of the hollow tube may include releasable end caps of the type described to further increase the life expectancy of the winding tube.
It should also be noted that while the end caps are preferably paper with a polymeric insert, an alternate construction could be all polymeric with a circumferential wear strip of a higher molecular weight material.
A peripheral starting groove is formed between the abutting ends of the hollow tube and end cap encircling the yarn carrier. The starting groove is formed with a relatively narrow locking portion extending around a portion preferably (approximately 90.degree. ) of the periphery of the tube and a relatively wider lead-in portion extending around the remaining portion of the periphery. The lead-in portion guides the first few turns of the waste bunch into the locking portion. The wider and narrower portions of the starting groove are formed by molding recesses into or chamfering one or both abutting ends of the hollow tube and/or end cap during the fabrication of the components.
It is therefore an object of the present invention to provide improvements in yarn carriers which make the tubes reusable by facilitating the cleaning of the starting groove.
It is another object of the present invention to provide a yarn carrier of the type described in which an end cap is releasably attached to the main body portion and forms a starting groove therebetween.
It is another object of the present invention to provide a yarn carrier of the type described in which the outer surface of at least the hollow tube is paper and the attachment means for joining the two are polymeric or metallic inserts which underlie the paper portion.